Recently, research has begun on operating bioreactor landfills. The bioreactor process involves the injection of liquid into the waste mass to accelerate waste degradation. The EPA and ARCADIS conducted a fugitive emission characterization study at the Three Rivers Solid Waste Technology Center Landfill located near Jackson, South Carolina. The survey area is a two acre research and development site that practices leachate recirculation and air injection. The focus of this study is to evaluate emissions of fugitive gases, such as methane and hazardous air pollutants, at the site using scanning open-path Fourier transform infrared spectrometers and open-path tunable diode laser absorption spectroscopy. The study involved a technique developed through research funded by the EPA National Risk Management Research Laboratory, which uses ground-based optical remote sensing technology, known as radial plume mapping. The horizontal radial plume mapping method was used to map surface methane concentrations, and the vertical radial plume mapping method was used to measure emissions fluxes downwind of the site.